What Is a Fluorescein Eye Stain Test?
A fluorescein eye stain test is
usually ordered if your doctor suspects you have damage on your cornea or
foreign objects in your eye. If you wear contact lenses, your doctor might do
this test to see whether the contacts are damaging your cornea.
During the test, a dark orange dye
called fluorescein is placed onto the outer surface of your eye. Based on the
staining, your doctor can identify any problems with your cornea and diagnose
Why Is the Test Done?
Your doctor may recommend a
fluorescein eye stain test if they suspect you have abrasions, or scratches, on
The cornea is a clear surface that
covers your outer eye. It’s made up of cells and proteins. Unlike most of your
body’s other tissues, the cornea contains no blood vessels. It’s protected and
nourished by lubrication such as tears.
It has two main functions: to
protect your eye from harmful irritants such as dust and germs, and to direct
light as it enters your eye.
The cornea is highly sensitive. If
it becomes scratched or damaged, new cells quickly cover the injury to prevent
infection from occurring. Deeper scratches will take longer to heal and may
cause scars. A fluorescein eye stain test can help your doctor detect corneal
injuries, small foreign objects or particles in the eye, and abnormal tear
production. The test may also help your doctor determine if your contact lenses
are irritating your corneas or causing any damage.
Where and How Is the Test Administered?
Your ophthalmologist (eye doctor)
will use either a small eyedropper or piece of blotting paper to place the dye
into your eye. They’ll ask you to blink several times to allow the dye to
spread over the surface of the cornea. Blinking spreads the dye throughout your
tear film — the wet surface of your eyeball that lubricates and protects the
eye. The tear film is made up of water, oil, and mucus.
You may feel a slight stinging
sensation when the dye is first applied. After a few moments, the dye will feel
like normal liquid on the eye and will no longer be uncomfortable. Your eye
surface may have a light yellow appearance.
Your ophthalmologist will then
shine a cobalt-blue light onto your eye through a tool made for examining eyes.
This tool is called a slit-lamp or ophthalmoscope. The combination of this
light and the dye will highlight any abnormalities or abrasions on the cornea.
From this, your ophthalmologist can determine the location of any problems and
evaluate the level of damage.
Understanding the Results
If your eye is healthy and your
cornea is undamaged, the dye will appear smooth across the entire surface of
Corneal abrasions or foreign particles
will cause abnormal results. These may be a result of:
- trauma to your eye, such as from a fingernail, make-up
brush, or other object
- dust, ash, or dirt that has blown into your eye
- a chemical burn
- rubbing your eyes too roughly
- old or improperly cleaned or fitted contact lenses
- any medical condition or situation where your eye is
open for a long time, which can dry out the cornea
- the presence of foreign bodies, such as an eyelash
In some cases, the damage could be
caused by abnormal tear production, or dry
eye. With this condition, you have
insufficient tears to nourish and protect the eye. This can lead to
inflammation of the cornea. Your test may also reveal a blocked tear duct.
What Are the Risks of the Test?
This test is risk-free. The
fluorescein dye may stain for a few days if it touches the skin around your
Preparing for the Test
In general, there’s nothing you
need to do to prepare for this test. If you wear contact lens, you’ll be asked
to take them out beforehand.
What to Expect After the Test
After the test, your doctor will
use the results to diagnosis any problems you’re having with your eyes. They’ll
meet with you to discuss the damage discovered on your cornea and plan any
Treatment options may include:
- removal of the foreign object from your eye
- using prescription eye drops or ointment, usually an
antibiotic to prevent an infection from developing
- using over-the-counter lubrication tear drops
- wearing a temporary eye patch or bandage contact lens
- leaving contact lenses out until the cornea has healed
- taking pain medications
If your injury has only affected
the surface of your cornea, it should heal in about two to three days. If your
injury has penetrated the surface of your eye, healing will take longer,
depending on the cause, size, and nature of your injury.